In order to increase a peak rate and user experience of a user, a node 1 (for example, a terminal or a base station) is usually not limited to receive data sent by a node 2 (for example, the base station or the terminal) on one carrier and one process. Correspondingly, the node 1 is required to feed back Hybrid Automatic Repeat Request (HARQ) information to the node 2. That is, whether a transmission block on each carrier/process is correct is detected. If the transmission block is correct, an Acknowledgement (ACK) is fed back. Otherwise, a Negative Acknowledgement (NACK) is fed back.
In a Long Time Evolution (LTE) system of the 3rd Generation Partnership Project (3GPP), the terminal (the node 1) is required to feed back the HARQ information according to a number of carriers configured by the base station (the node 2) and a transmission mode of each carrier. If the transmission modes of the carriers adopt a space multiplexing mode, for example, each carrier has two transmission blocks, 2-bit HARQ information is required to be fed back for each carrier. Otherwise, 1-bit HARQ information (each carrier has one transmission block) is required to be fed back for each carrier. For example, in case that a network configures five carriers to the terminal and a transmission mode of each carrier is the space multiplexing mode, the terminal is required to feed back 10-bit HARQ information to the network in an uplink subframe.
In addition, if the carriers are Time Division Duplexing (TDD) carriers, the terminal is further required to feed back the HARQ information according to uplink and downlink configurations of the carriers. For example, if the network configures a TDD carrier to the terminal and an uplink and downlink configuration of the carrier is a configuration 5, the terminal is required to feed back HARQ information (one transmission block for each subframe, totally nine bits) of nine downlink subframes in the uplink subframe. For another example, in case that the network configures two TDD carriers to the terminal, uplink and downlink configurations of the carriers are both the configuration 5, the terminal is required to feed back HARQ information (18 bits) of 18 downlink subframes in the uplink subframe. However, in carrier aggregation enhancement research projects of the 3GPP in a related technology, the node 2 may configure up to 32 carriers to the node 1. For Frequency Division Duplexing (FDD), in case of non-space multiplexing, HARQ information required to be fed back is 32 bits, and in case of space multiplexing, a bit number of HARQ information required to be fed back is 64. For TDD, the number of bits of a HARQ required to be fed back is related to uplink and downlink configuration information. In case of the uplink and downlink configuration 5, the number of bits of HARQ information required to be fed back is up to 288.
In the related technology, for reasons such as reducing control signaling overhead and power consumption, improving coverage, reducing implementation complexity and the like, the node 1 is usually required to reduce the number of bits of the HARQ information required to be fed back to the node 2. A common method for this is to bind HARQ information of multiple transmission blocks on the same predefined time domain or space domain. For example, pieces of HARQ information of two transmission blocks on a time domain or space domain of the same carrier are bound. When it is detected that both of the two transmission blocks are correct, a 1-bit ACK is fed back. Otherwise, a 1-bit NACK is fed back. In such a manner, HARQ feedback overhead may be reduced to be a half of the original.